The incidence of metabolic diseases in cows and buffaloes increases as the milk production increases and the herd size becomes larger. The highest incidences are noted in the period commencing from calving to the peak of lactation. The extremely high turn over of fluids, salts and soluble organic matters during the early lactation period may be beyond the capacity of an individual animal’s metabolic reserves to maintain physiological level of a particular nutrient resulting in development of metabolic diseases. For example, milk fever occurs when the demand of calcium for onset of lactation is greater than its availability in cow’s diet or supply from skeleton reserves. Inadequate quantity of a nutrient or its malabsorption or maldigestion during high metabolic requirement causes negative balance and onset of metabolic diseases. Pregnancy toxaemia in ewes, fat cow syndrome in dairy cattle and hyperlipaemia in horses are some examples of negative nutrient balance. Some production induced metabolic diseases like exertional rhabdomyolysis (azoturia) are predisposed by management practices. Imbalance diet can also contribute to production diseases. For example, a diet may contain adequate quantity of protein but may be deficient in carbohydrate precursor required to meet milk production demand.